1. Technical Field
This disclosure relates generally to processing data arranged on a physical recording medium, and more specifically to reclaiming blocks of data for further use.
2. Description of the Related Art
Within a physical recording medium, blocks of data may be reclaimed for further use. For example, in the solid-state storage media context, a set of data is typically written to solid-state storage media by performing an erase operation on a group of cells followed by a program operation on those cells. Because of the small size of these cells and the high voltages used to perform these operations, the cells can only be erased and programmed a limited number of times before the transistors within the cells begin to degrade.
To improve the longevity of these cells, modern systems may arrange data on a recording medium using a log-structure to ensure that writes to cells are more evenly distributed across the medium to produce better wear leveling (as opposed to writing particular cells frequently while other cells go unused). When storing data using a log-structured format, data may be written at an append point that starts at an initial portion in the medium and advances forward in the log as writes are performed. Accordingly, when portions of data are updated, rather than overwriting those portions of the media with the updated data, the previously stored portions of the data may instead be invalidated as updated versions of the data are written to the append point in the medium. The cells storing the invalid data may eventually be erased in order to permit the cells to be programmed to store subsequent data.
In some instances, a system may execute a process that is responsible for identifying blocks of cells with invalid data and erasing those blocks. This process of reclaiming blocks of data for subsequent use is sometimes referred to as “garbage collection.” In the solid-state storage context, reclamation may include identifying and erasing blocks of data.